Method and/or system for tree transformation

ABSTRACT

Embodiments of methods, apparatuses, devices and/or systems for manipulating hierarchical sets of data are disclosed.

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 60/648,950, filed on Jan. 31, 2005, and assigned tothe assignee of claimed subject matter.

BACKGROUND

This disclosure is related to hierarchical data arrangements and, moreparticularly, to manipulating such data arrangements.

In a variety of fields, data or a set of data, may be represented in ahierarchical fashion. This form of representation may, for example,convey information, such as particular relationships between particularpieces of data and the like. However, manipulating such datarepresentations is not straight-forward, particularly where the data isarranged in a complex hierarchy. Without loss of generality, one examplemay include a relational database. Techniques for performing operationson such a database, for example, are computationally complex orotherwise cumbersome. A continuing need, therefore, exists foradditional techniques for manipulating data hierarchies.

BRIEF DESCRIPTION OF THE DRAWINGS

Subject matter is particularly pointed out and distinctly claimed in theconcluding portion of the specification. The claimed subject matter,however, both as to organization and method of operation, together withobjects, features, and advantages thereof, may best be understood byreference of the following detailed description when read with theaccompanying drawings in which:

FIG. 1 is a schematic diagram of one embodiment of a tree;

FIG. 2 is a schematic diagram illustrating one embodiment of a binaryedge labeled tree (BELT);

FIG. 3 is a schematic diagram illustrating another embodiment of a BELT;

FIG. 4 is a schematic diagram illustrating an embodiment of a binaryedge labeled string;

FIG. 5 is a schematic diagram of an embodiment of a node labeled tree;

FIGS. 6-10 are schematic diagrams illustrating a process to transform anode labeled tree to a BELT according to an embodiment;

FIGS. 11-16 are schematic diagrams illustrating a process to transform anode labeled tree comprising one or more null node label values to aBELT according to an embodiment;

FIGS. 17-22 are schematic diagrams of trees illustrating atransformation of an unlabeled tree to a BELT according to anembodiment;

FIG. 23 is a schematic diagram associating particular node label valueswith portions of BELTs according to an embodiment of the BELT shown inFIG. 22;

FIG. 24 is a flow diagram illustrating a process of associating nodelabel values with BELTs and/or portions of BELTs according to anembodiment;

FIG. 25 is a table illustrating a particular embodiment of anassociation between numerals and BELTs and/or portions of BELTs;

FIG. 26 illustrates a representation of node label values as a portionof a BELT according to an embodiment;

FIG. 27 is a table illustrating a particular embodiment of anassociation between natural numerals and BELTs; and

FIG. 28 is a table illustrating a portion of the Kleene enumeration ofnon-composite numerals.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are setforth to provide a thorough understanding of the claimed subject matter.However, it will be understood by those skilled in the art that theclaimed subject matter may be practiced without these specific details.In other instances, well-known methods, procedures, components and/orcircuits have not been described in detail so as not to obscure theclaimed subject matter.

Some portions of the detailed description which follow are presented interms of algorithms and/or symbolic representations of operations ondata bits or binary digital signals stored within a computing systemmemory, such as a computer memory. These algorithmic descriptions and/orrepresentations are the techniques used by those of ordinary skill inthe data processing arts to convey the substance of their work to othersskilled in the art. An algorithm is here, and generally, considered tobe a self-consistent sequence of operations and/or similar processingleading to a desired result. The operations and/or processing involvephysical manipulations of physical quantities. Typically, although notnecessarily, these quantities may take the form of electrical and/ormagnetic signals capable of being stored, transferred, combined,compared and/or otherwise manipulated. It has proven convenient attimes, principally for reasons of common usage, to refer to thesesignals as bits, data, values, elements, symbols, characters, terms,numbers, numerals and/or the like. It should be understood, however,that all of these and similar terms are to be associated with theappropriate physical quantities and are merely convenient labels. Unlessspecifically stated otherwise, as apparent from the followingdiscussion, it is appreciated that throughout this specificationdiscussions utilizing terms such as “processing”, “computing”,“calculating”, “determining” and/or the like refer to the actions and/orprocesses of a computing platform, such as a computer or a similarelectronic computing device, that manipulates and/or transforms datarepresented as physical electronic and/or magnetic quantities within thecomputing platform's memories, registers, and/or other informationstorage, transmission, and/or display devices.

In a variety of fields, data or sets of data may be represented in ahierarchical fashion. This form of representation may, for example,convey information, such as particular relationships between particularpieces of data and the like. However, manipulating such datarepresentations is not straight forward, particularly where the data isarranged in a complex hierarchy. Without loss of generality, one examplemay include a relational data base. Techniques for performing operationson such a data base for example, may be computationally complex orotherwise cumbersome. A continuing need, therefore, exists foradditional techniques for manipulating data hierarchies.

As previously discussed, in a variety of fields, it is convenient ordesirable to represent data, a set of data and/or other information in ahierarchical fashion. In this context, such a hierarchy of data shall bereferred to as a “tree.” In a particular embodiment, a tree may comprisea finite, rooted, connected, unordered, acyclic graph. This isillustrated here, for example, in FIG. 1 by embodiment 100. Asillustrated, the root of this particular embodiment encompasses node105. In addition to 105, there are eight other nodes designated 110 to140, respectively. Likewise, the nodes are connected by branchesreferred to, in this context, as edges. Thus, the nodes of this tree areconnected by eight edges. This embodiment, therefore, illustrates afinite tree that is rooted by node 105. Furthermore, the nodes areconnected, meaning, in this context, that a path exists between any twonodes of the tree. The tree is likewise acyclic, meaning here, that nopath in the tree forms a complete non-backtracking loop. Here, unorderedrefers to the notion that there is no implied ordering or precedenceamong nodes attached to a common node, despite the appearance ofordering in a graphical illustration.

As previously suggested, in a variety of contexts, it may be convenientand/or desirable to represent a hierarchy of data and/or otherinformation using a structure, such as the embodiment illustrated inFIG. 1. One particular embodiment, without loss of generality, of a treemay include edges that are labeled with data and/or other values.Likewise, in one particular embodiment, such data or values may belimited to binary data, that is, in this example, either a binary one ora binary zero. Here, such an embodiment may be referred to as a binaryedge labeled tree (BELT), as shall be discussed in more detailhereinafter.

One example of a BELT is illustrated by embodiment 200 of FIG. 2. Thus,as illustrated, the edges of the BELT shown in FIG. 2 are labeled witheither a binary zero or binary one. FIG. 3 illustrates anotherembodiment 300 of a different binary edge labeled tree. It is noted thatthis tree is similar or isomorphic to the embodiment of FIG. 2.

A subset of BELTs may be referred to in this context as binary edgelabeled strings (BELSs). One embodiment, 400, is illustrated in FIG. 4.Thus, as illustrated by embodiment 400, this particular binary edgelabeled string comprises four nodes and three edges, where the edges arelabeled, respectively, binary zero, binary one and binary zero. Thus, abinary edge labeled string comprises a binary edge labeled tree in whicheach node has no more than two edges. To reiterate, in this context, astring comprises a binary edge labeled string and a tree comprises abinary edge labeled tree if each edge of the string or tree respectivelystores a single bit. Likewise, in this context, two nodes are employedto support an edge holding, storing and/or representing a single pieceof binary data. At this point, it is worth noting that strings and treeshaving nodes and edges, such as previously described, may be representedin a computing platform or similar computing device through a datastructure or a similar mechanism intended to capture the hierarchicalrelationship of the data. It is intended that all such embodiments areincluded within the scope of the claimed subject matter.

In addition to, or as an alternative to storing, holding and/orrepresenting information in edges of a tree in an edge labeled tree, atree may similarly store, hold and/or represent information in nodes ofa tree. Here, such a tree storing, holding and/or representinginformation in node of a tree may comprise a “node labeled tree” inwhich information may be stored, held and/or represented in node labelvalues associated with particular nodes. Additionally, a tree storing,holding and/or representing information in nodes and edges may comprisea “feature tree” in which information may be stored, held and/orrepresented in node label values and/or edge label values. Accordingly,edge labeled trees and node labeled trees comprise particular types oftrees in a greater class of trees known as feature trees.

While node and edge labeled trees may be used to express hierarchicaldata, a tree may not necessarily store, hold and/or representinformation in any of its nodes or edges. For example, an “unlabeledtree” may represent hierarchical data without having any informationstored, held or represented in any of its edges or nodes (including rootnodes and/or terminal nodes). Rather, such hierarchical data may beexpressed in how nodes and/or edges in an unlabeled tree may relate toother nodes and/or edges.

According to an embodiment, a “set” may define a collection of uniqueunordered elements or members. For example, for the purpose ofillustration, a set may contain members or elements of a distinctclassification, such as the set of all automobiles in a parking lot of aparticular color. In a particular embodiment, trees may be classifiedinto sets defined by certain characteristics, such as the set containingnode labeled trees, BELTs, unlabeled trees, and the like. However, thisis merely an example of how trees may be classified into distinct setsand the claimed subject matter is not limited in this respect.

According to an embodiment, a “transformation” may define a process bywhich elements of a first set may be mapped into and/or associated withelements of a second set. For example, in a particular embodiment, atransformation may map and/or associate a member of the set of unlabeledtrees with a member of the set of node labeled trees. Similarly,according to a particular embodiment, a transformation may map and/orassociate a member of the set of node labeled trees with a member of theset of BELTs. Likewise, a transformation may map and/or associate amember of the set of unlabeled trees with a member of the set of BELTs.However, these are merely examples of how a transformation may mapand/or associate members of one set to members of another set, and theclaimed subject matter is not limited in these respects.

According to an embodiment, a transformation may associate and/or map anelement in a first set with an element in a second set as an “elementaryequivalent.” Here, in a particular embodiment, such a transformation mayassociate such elementary equivalent elements in different sets in aone-to-one and onto mapping in which the transformation defines forelements in a first set corresponding, unique elementary equivalents ina second set. Similarly, a transformation may also map and/or associatemembers of the second set to corresponding elementary equivalents in thefirst set. Examples of a transformations mapping and/or associatingelementary equivalent elements of different sets may be found in, forexample, Logical Number Theory, An Introduction, by Craig Smorynski, p.305. In a particular embodiment, for example, a transformation may mapand/or associate trees of a first type (e.g., a member of the set ofunlabeled trees, node labeled trees or BELTs) to elementary equivalenttrees of a second type. However, this is merely an example of how atransformation may map and/or associate members of different sets aselementary equivalents, and the claimed subject matter is not limited inthese respects.

Also, operations and/or manipulations of elements in a first set mayprovide elements that are also in the first set. For example, for thepurpose of illustration, the addition of positive integers (the firstset) to positive integers results in positive integers. According to anembodiment, operations and/or manipulations on a tree of a particulartype (e.g., unlabeled tree, node labeled tree or BELT) may result inanother tree of the same type, for example.

A transformation of elements in a first set to elementary equivalents ina second set may also map and/or associate results from an operationand/or manipulation of the elements of the first set to elementaryequivalents of the results in the second set. For the operation and/ormanipulation of the elements in the first set, a corresponding operationand/or manipulation may exist for elements in a second set which areelementary equivalents of the elements of the first set. Here, thecorresponding operation and/or manipulation of elements in the secondset may provide elementary equivalents of the results of the operationand/or manipulation of the elements in the first set. Continuing withthe example of the addition of positive integers, for the purpose ofillustration, the set of negative integers may comprise a set ofelements that are elementary equivalents of positive integers mappedand/or associated by a transformation comprising multiplication bynegative one. Here, addition of negative integers provides a negativeinteger which may comprise an elementary equivalent of a sum resultingfrom the addition of positive integers (which themselves compriseelementary equivalents of the added negative integers).

According to an embodiment, an operation and/or manipulation of a firsttree of a particular first type (representing hierarchical data) mayresult in a second tree of the first type. Here, a transformationassociating and/or mapping the first tree of the first type to anelementary equivalent first tree of a second type may also map thesecond tree of the first type to an elementary equivalent second tree ofthe second type. Here, a corresponding operation and/or manipulation onthe first tree of the second type may provide the second tree of thesecond type. However, these are merely examples of how a transformationmay associate and/or map elements of a first set with elements of asecond set as elementary equivalents, and the claimed subject matter isnot limited in these respects.

Binary edge labeled trees and binary node labeled trees may be employednearly interchangeably to represent substantially the same hierarchy ofdata. In particular, a binary node labeled tree may be associated with abinary edge labeled tree in which the nodes of the binary node labeledtree take the same values as the edges of the binary edge labeled tree,except that the root node of the binary node labeled tree may comprise anode having a zero value or a null value. Thus, rather than employingbinary edge labeled trees to express hierarchical data, the hierarchicaldata may alternatively be expressed in corresponding binary node labeledtrees.

As discussed above, operations and/or manipulations of trees maycorrespond with operations and/or manipulations of the hierarchical datarepresented in such trees. Similarly, operations and/or manipulations oftrees of a particular type (e.g., unlabeled trees) may correspond withoperations and/or manipulations of elementary equivalent trees of adifferent type (e.g., node labeled trees and/or BELTs). Here, atransformation may associate and/or map trees of the first type to treesof the second type as elementary equivalents.

Operations on trees may, in some situations, be efficient for processinghierarchical data in the form of a BELT. According to an embodiment, itmay be desirable to transform an unlabeled tree to a node labeled treeand/or BELT. Here, the BELT resulting from the transformation maycomprise an elementary equivalent of the original unlabeled tree byexpressing essentially the same hierarchical data as the unlabeled tree.Accordingly, operations on the hierarchical data expressed in theunlabeled tree may be carried out on the resulting BELT. For example,expressing hierarchical data of an unlabeled tree in a BELT may enablegreater efficiency in indexing the hierarchical data for processing.Also, expression of hierarchical data of an unlabeled tree in the formof a BELT may enable an expression of the hierarchical data as a binarystring that may use less memory for storage of the hierarchical data,for example. However, these are merely examples of potential or possibleadvantages to transforming an unlabeled tree to a BELT and the claimedsubject matter is not limited in these respects.

In accordance with the claimed subject matter, therefore, any tree,regardless of whether it is binary edge labeled, binary node labeled,non-binary, a feature tree, or otherwise, may be manipulated and/oroperated upon. For example, and as shall be described in more detailbelow, a node labeled tree in which the nodes are labeled with naturalnumerals or data values may be transformed to a binary edge labeledtree. Furthermore, this may be accomplished with approximately the sameamount of storage. For example, for this particular embodiment, this mayinvolve substantially the same amount of node and/or edge data labelvalues.

As previously noted, the claimed subject matter is not limited in scopeto this particular example, however, as illustrated in more detailhereinafter, the tree illustrated in FIG. 5 may be transformed to abinary edge labeled tree through a sequence of processing depicted hereas graph operations, although such a transformation may alternatively beimplemented by operations implemented otherwise, one such example beingby a computing platform, for example. Alternatively, it may bedesirable, depending upon the particular embodiment, to transform treesto, for example, binary node labeled trees. Likewise, other embodimentsin which trees of one form are transformed to trees of another form arealso included within the scope of the claimed subject. In this example,a particular tree, embodiment 1100, is illustrated in FIG. 5, comprisesa node labeled tree rather than an edge labeled tree.

According to an embodiment, trees or portions of trees may berepresented by natural numerals according to an association of trees andnatural numerals. Without belaboring the present discussion, additionaldescriptions of how natural numerals may be associated with trees isdiscussed in greater detail below and in U.S. patent application Ser.No. 11/005,859, filed on Dec. 6, 2004, by J. J. LeTourneau, titled,“Manipulating Sets of Hierarchical Data,” assigned to the assignee ofthe presently claimed subject matter. It should be understood, however,that while the particular embodiments illustrated are directed toparticular associations of numerals and trees, there may be manyassociations of trees to numerals according to corresponding particular“association embodiments,” and the claimed subject matter is not limitedto any such particular association.

According to an embodiment, a transformation of node labeled tree 1100to a BELT makes use of an association of BELTs and/or portions of BELTswith numerals according to a particular association embodiment. Asillustrated below, according to a particular embodiment, node labelvalues of node labeled tree 1100 may express essentially the sameinformation of BELTs or portions of a BELT. Accordingly, such atransformation may comprise, at least in part, replacing at least someof the node label values with corresponding BELTs or portions of BELTs.

Referring now to FIG. 5, node values are deleted for those nodes storingthe value zero. This is illustrated, for example, in FIG. 6. Node valuesare also deleted for the nodes storing the value one. In this case, anew single unlabeled node is attached to those nodes that had stored thevalue one, and the edge between the prior node and the new node islabeled with a zero value. This is illustrated, for example, in FIG. 7.For nodes with a label value k that is a power of 2, and larger thanone, the node label value is deleted and (log₂(k)+1) new nodes areattached, labeling the edge between the new nodes and the old nodes witha zero value. This, for example, is illustrated in FIG. 8.

The remaining node label values comprise non-powers of two that arethree or larger. These node label values are factored into one or morenon-composite numerals. For such a resulting non-composite numeralfactor of a node's label value, a tag representing the non-compositenumeral factor may be connected to the node by an edge having an edgelabel value of binary zero. The tag may comprise a portion of a BELTrepresenting the non-composite numeral factor according to anassociation of BELTs and numerals of a particular associationembodiment. Such an association of BELTs and numerals is illustrated indetail below. However, it should be understood that this is merely anexample of an association of numerals and BELTs and that the claimedsubject matter is not limited in these respects. This is illustrated,for example, in FIG. 9. The remaining edges of the tree are labeled witha binary value of one. This is illustrated in FIG. 10.

In another embodiment, however, a particular tree may include null typesor, more particularly, some node values denoted by the empty set. Thisis illustrated, for example, by the tree in FIG. 11, although, ofcourse, this is simply one example. An advantage of employing null typesincludes the ability to address a broader array of hierarchical datasets. For example, without loss of generality and not intending to limitthe scope of the claimed subject matter in any way, a null type permitsrepresenting in a relational database, as one example, situations inwhich a particular attribute does not exist. As may be appreciated, thisis different from a situation, for example, where a particular attributemay take on a numeral value of zero. Thus, it may be desirable to beable to address both situations when representing, operating upon and/ormanipulating hierarchical sets of data.

A particular application of null node label values may be applied to atransformation of BELTs to binary node labeled trees (BNLTs). WhileFIGS. 2 through 4 illustrate specific examples of BELTs, it should beunderstood that the information expressed in a BELT may compriseessentially the same information represented in a BNLT having the samestructure of corresponding nodes and edges. Here, a transformation froma BELT to a BNLT may comprise assigning node label values to nodes inthe resulting BNLT the edge label values of edges in the BELT connectingcorresponding nodes to their parents. The root node in the resultingBNLT may then be assigned a null label value. Similarly, a BNLT may betransformed to a BELT by assigning label values of nodes to edgesconnecting the nodes to corresponding parent nodes. As such, BELTs andBNLTs may comprise members of class of trees called binary labeled trees(BLTs) in which either nodes or edges hold, store and/or represent abinary label value.

For this particular embodiment, a tree with nulls, as described above,may be transformed to a tree without nulls. This shall be illustrated,for example, for nodes labeled with a null, such as for the tree in FIG.11; however, the claimed subject matter is not limited in scope in thisrespect, of course. In this particular embodiment, the nulls are deletedfrom those nodes having a null. This is illustrated, for example, byFIG. 12.

Referring now to FIG. 13, node values are also deleted for those nodesstoring the value zero. Furthermore, a single new node is attached tothe nodes previously storing the zero values. The edge between the priornodes and the new nodes are labeled with a zero value. For nodes with avalue k that is a power of two, including the value one, the node valueis deleted and (log₂(k)+2) new nodes are attached, labeling the edgebetween the new nodes and the old nodes with a zero value. This isillustrated, for example, in FIG. 14.

The remaining node label values comprise non-powers of two that arethree or larger. These node label values are factored into one or morenon-composite numerals. For such a resulting non-composite numeralfactor of a node's label value, a tag representing the non-compositenumeral factor may be connected to the node by an edge having an edgelabel value of binary zero. The tag may comprise a portion of a BELTrepresenting the non-composite numeral factor according to anassociation of BELTs and numerals of a particular associationembodiment. Such an association of BELTs and numerals is illustrated indetail below. However, it should be understood that this is merely anexample of an association of numerals and BELTs and that the claimedsubject matter is not limited in these respects. This is illustrated,for example, in FIG. 15. The remaining edges are labeled with a binaryvalue of one. This tree is illustrated, for example, in FIG. 16.

In an alternative embodiment, a node labeled tree may comprise fixedlength tuples of numerals. For such an embodiment, such multiplenumerals may be combined into a single numeral, such as by employingCantor pairing operations, for example. See, for example, Logical NumberTheory, An Introduction, by Craig Smorynski, pp, 14-23, available fromSpringer-Verlag, 1991. This approach should produce a tree to which thepreviously described embodiments may then be applied. Furthermore, forone embodiment, a tree in which nodes are labeled with numerals ornumerical data, rather than binary data, may be transformed to a binaryedge labeled tree and/or binary node labeled tree, and, for anotherembodiment, a tree in which edges are labeled with numerals or numericaldata, rather than binary data, may be transformed to a binary edgelabeled tree and/or binary node labeled tree.

FIGS. 17 through 22 are schematic diagrams of trees illustrating atransformation of an unlabeled tree to a BELT according to anembodiment. This is illustrated as a sequence of operations depictedhere as graph operations, although such a transformation mayalternatively be implemented by operations implemented otherwise, onesuch example being by a computing platform, for example. Likewise, otherembodiments in which trees of one form are transformed to trees ofanother form are also included within the scope of the claimed subjectmatter.

FIG. 17 is a schematic diagram of an unlabeled tree 2300 comprising aroot node 2302 according to an embodiment. Identifying root node 2302indicates a directional flow of hierarchical data represented inunlabeled tree 2300 descending away from root node. In addition tohaving a root node to indicate the directional flow of the hierarchicaldata, one or more nodes in the tree may be identified as “terminalnodes” having no children or offspring nodes. Hence, identification ofthe terminal nodes in a tree indicates a directional flow ofhierarchical data ascending away from the terminal nodes toward a rootnode.

FIG. 18 is a schematic diagram of unlabeled tree 2300 showing terminalnodes as cross-hatched nodes. As illustrated from FIG. 18, a tree maycomprise a single root node but multiple terminal nodes. According to anembodiment, a tree may comprise one or more nodes which are “frontiernodes.” A frontier node is connected to one or more child nodes and doesnot have any grandchild nodes. In other words, a frontier node has atleast one child node and all nodes descending from a frontier node areterminal nodes. As illustrated in FIG. 19, by way of example, accordingto a particular embodiment, frontier nodes 2304 in tree 2300 areconnected to one or more corresponding child terminal nodes. Also, atleast some of the terminal nodes are not directly connected to afrontier node.

FIGS. 20 through 22 are schematic diagrams illustrating a process totransform unlabeled tree 2300 to a BELT that comprises an elementaryequivalent of unlabeled tree 2300. In this particular embodiment,unlabeled tree 2300 may represent hierarchical data and thetransformation illustrated below may map unlabeled tree 2300 to a BELTthat represents essentially the same hierarchical data. According to anembodiment, tree 2300 is transformed to a node labeled tree 2500 shownin FIG. 21 which comprises an elementary equivalent of tree 2300. Then,as illustrated above, node labeled tree 2500 may be transformed to aBELT 2600 shown in FIG. 22 which comprises an elementary equivalent oftree 2600. Accordingly, in a particular embodiment, the resulting tree2600 comprises an elementary equivalent of tree 2300. However, this ismerely an example of how an unlabeled tree may be transformed to a BELTthat is an elementary equivalent of the unlabeled tree and the claimedsubject matter is not limited in this respect.

According to an embodiment, FIG. 20 illustrates a process of “pruning”terminal nodes in tree 2300 from frontier nodes. Here, tree 2400 showsdarkened nodes 2404 which correspond with frontier nodes 2304 of tree2300. According to an embodiment, tree 2400 may be generated by pruningand/or removing one terminal node connected to each of the correspondingfrontier nodes 2304. The remaining terminal nodes of tree 2300 (i.e.,the unpruned terminal nodes) are indicated with cross-hatching. However,this is merely an example of how terminal nodes may be pruned fromcorresponding frontier nodes and the claimed subject matter is notlimited in this respect.

FIG. 21 is a schematic diagram of a node labeled tree 2500 which may bedetermined, at least in part, from tree 2400. According to anembodiment, the remaining terminal nodes of tree 2300 indicated withcross-hatching in tree 2400 are replaced with node label valuesassociated with parent nodes in tree 2500. In a particular embodiment,for example, nodes in tree 2400 having a natural numeral k of suchremaining terminal nodes as children are associated with nodes in tree2500 having a node label value of k and the remaining terminal nodechildren in tree 2400 are removed in the resulting tree 2500. Again,tree 2500 may represent essentially the same hierarchical datarepresented in tree 2400. Here, the resulting node labeled tree 2500determined from the above described transformation may comprise anelementary equivalent of unlabeled tree 2300. However, this is merely anexample how an unlabeled tree may be transformed to an elementaryequivalent node labeled tree and the claimed subject matter is notlimited in this respect.

Nodes in tree 2500 contain a numeral as a node label value to representa count of remaining terminal nodes removed from corresponding nodes intree 2400. While not shown in FIG. 21, the remaining nodes in tree 2500not showing a node label may nevertheless be assigned a node label valueof natural numeral “0.” According to an embodiment, tree 2500 may betransformed to an elementary equivalent BELT by replacing nodes in tree2500 having a non-zero node label value with an equivalent portion of aBELT. In a particular embodiment, the portion of a BELT equivalent tothe non-zero node label value may be determined according to anassociation embodiment of numerals and trees.

FIG. 22 is a schematic diagram of a BELT 2600 resulting from atransformation from node labeled tree 2500 according to an embodiment.According to a particular embodiment, edges in BELT 2600 correspondingwith edges existing in node labeled tree 2500 may be labeled with anumeral “1.” Then, nodes in BELT 2600 corresponding to nodes in nodelabeled tree 2500 having non-zero node label values may be connected toportions of BELTs which are based, at least in part, on the non-zerolabel values. Here, the non-zero node label values may be associatedwith the portions of BELTs according to an association of BELTs andnumerals according to a particular association embodiment. In thisparticular embodiment, for the purpose of illustration, FIG. 23 showsportions of BELTs in BELT 2600 corresponding with a non-zero node labelvalue in node labeled tree 2500. FIG. 23 also shows non-zero node labelvalues in node label tree 2500 above corresponding to portions of BELTsin BELT 2600. Here, the edge between the prior nodes and the new nodesis labeled with a zero value. For nodes with a value k that is a powerof two, including the value one, the node value is deleted and(log₂(k)+1) new nodes are attached, labeling the edge between the newnodes and the old nodes with a zero value.

The remaining node label values comprise non-powers of two that are 3 orlarger. These node label values may be factored into one or morenon-composite numerals according to a particular association embodiment.For such a resulting non-composite numeral factor of a node's label, atag representing the non-composite numeral factor may be connected tothe node by an edge having an edge label value of binary zero. The tagmay comprise a portion of a BELT representing the non-composite numeralfactor according to an association of BELTs and numerals of a particularassociation embodiment.

As described below in greater detail, the association of portions ofBELTs and numerals may associate unique portions of BELTs andcorresponding numerals. In other words, in a particular associationembodiment, for any numerical node label value there is a uniquecorresponding BELT portion. Accordingly, the resulting BELT 2600 mayexpress essentially the same hierarchical data as the node labeled tree2500 and comprise an elementary equivalent of the node labeled tree2500. However, it should be understood that this is merely an example ofhow a node labeled tree may be transformed to an elementary equivalentBELT and the claimed subject matter is not limited in these respects.Since the node labeled tree 2500 comprises an elementary equivalent ofthe unlabeled tree 2300, BELT 2600 may also comprise an elementaryequivalent of unlabeled tree 2300. However, again, this is merely anexample of a transformation of an unlabeled tree to an elementaryequivalent BELT and the claimed subject matter is not limited in theserespects.

FIG. 24 is a flow diagram illustrating a process 2700 of associatingnode label values with BELTs and/or portions of BELTs according to anembodiment of the transformation illustrated above with reference toFIGS. 21 through 23. Here, process 2700 may be used to associate nodelabel values of nodes in node labeled tree 2500 with correspondingportions of BELTs in BELT 2600, according to the particular associationembodiment illustrated in FIG. 23. FIG. 25 is a table showing aparticular association embodiment that may be determined according toprocess 2700. However, it should be understood that process 2700 andFIG. 24 merely illustrate particular association embodiments and thatthe claimed subject matter is not limited in these respects.

Process 2700 may determine BELT portions corresponding to node labels“k” of a node label tree, as illustrated in the transformation from nodelabeled tree 2500 to BELT 2600 illustrated above. If a particular nodelabel value k is equal to zero, as determined at diamond 2704, process2700 merely removes any node label value from a corresponding node inthe resulting BELT. For a particular node label value k equal to one, asdetermined at diamond 2706, block 2708 may attach to a correspondingnode in the resulting BELT a single node by an edge having a label valueof binary zero. Such a BELT portion corresponding to numeral “1” isshown in the association embodiment of FIG. 25.

For a particular node label value k equal to a power of two, asdetermined at diamond 2712, block 2710 may attach to a correspondingnode in the resulting BELT, log₂(k)+1 nodes by corresponding edgeshaving a label value of binary zero. This is illustrated in theparticular association embodiment shown in FIG. 25 with reference toBELT portions corresponding to numerals two, four and eight. Here, twonodes are attached to the corresponding node in the resulting BELT bycorresponding edges for a node label value k=2. Three nodes are attachedto the corresponding node in the resulting BELT by corresponding edgesfor a node label value k=4; and four nodes are attached to thecorresponding node in the resulting BELT by corresponding edges for anode label value k=8.

According to an embodiment, a node label value k may comprise a naturalnumeral that is a product of natural numerals x and y greater than one.Under this condition, k comprises a “composite numeral” capable of beingfactored into natural numerals x and y. Here, the BELT portionrepresenting k in a resulting BELT may be represented as a merger ofrespective BELT portions represented by the natural numerals x and y ata corresponding node in the resulting BELT providing, in effect, a rootnode for the merged BELT portions. Alternatively, a node label value kmay comprise a “non-composite” natural numeral that cannot be factoredinto positive natural numerals other than one and itself.

Returning to process 2700, if a node label value k comprises anon-composite natural numeral greater than three, as determined atdiamond 2716, block 2714 may attach a BELT portion associated with thenon-composite numeral to a corresponding node in the resulting BELT.Here, the BELT portion may be determined from a particular associationof BELTs with non-composite numerals.

Returning again to process 2700, if a node label value k comprises acomposite natural numeral, as determined at diamond 2716, block 2718 mayfirst factor k by the largest power of two, “w”. This factor may berepresented by a BELT portion comprising log₂(w) nodes attached to thecorresponding node in the resulting BELT by corresponding edges withlabel values “0.” The remainder may then be factored into non-compositenumerals greater than two. According to a particular associationembodiment, as illustrated with reference to block 2714, for example,block 2718 may determine BELT portions corresponding to thesenon-composite factors of the remainder. Here, for such a resultingnon-composite numeral factor of a node's node label, a tag representingthe non-composite numeral factor may be connected to the node by an edgehaving an edge label value of binary zero. The tag may comprise aportion of a BELT representing the non-composite numeral factoraccording to an association of BELTs and numerals of a particularassociation embodiment. Such an association of BELTs and numeralsaccording to one particular embodiment is illustrated in detail below.

According to a particular association embodiment, a composite numeralmay be represented by individual BELTs and/or BELT portionscorresponding with individual factors making up the composite numeral.Here, a “merger” operation may join the BELTs and/or BELT portionscorresponding with the individual factors at a common root node to formthe BELT and/or BELT portions corresponding with the composite numeral.Accordingly, such a merger operation of BELTs at a root node maycorrespond with multiplication of numerals corresponding with the mergedBELTs. Without belaboring the discussion, such a merger operation isfurther illustrated in the aforementioned U.S. patent application Ser.No. 11/005,859, filed on Dec. 6, 2004, by J. J. LeTourneau, titled,“Manipulating Sets of Hierarchical Data.”

Returning to process 2700, block 2720 may merge the BELT portionscorresponding to these non-composite factors determined at block 2718,and any BELT portion corresponding to a power of two factor “w” of k, atthe corresponding node in the resulting BELT. As illustrated in FIG. 26,by way of example, a node value of 1950 may be factored at block 2718into non-composite numerals as follows:1950=2×3×5×5×13As may be observed from FIG. 26, according to the particular associationembodiment illustrated in FIG. 25, the BELT portion corresponding tonumeral 1950 comprises a merger of BELT portions corresponding to theindividual non-composite factors 3, 5, 5 and 13. For the remainingfactor “2,” an additional node is connected by an edge having a labelvalue of binary zero. Accordingly, it should be recognized for thisparticular embodiment that while block 2710 may attach log₂(k)+1 nodesin the resulting BELT for a node label value power of two k, block 2720may merge log₂(w) nodes for a power of two factor w of a composite nodelabel value (with BELT portions representing non-composite factorsgreater than two).

Process 2700 should be understood to be merely illustrative of aparticular process for generating BELT portions corresponding to nodelabel values in a corresponding node labeled tree. In alternativeembodiments, possible node label values may be associated in a look uptable with corresponding BELT portions determined, at least in part,according to a particular association embodiment.

Regarding particular association embodiments, FIG. 25 shows that thenumber of nodes representing non-composite numerals may grow roughlylogarithmically with respect to the corresponding non-compositenumerals. Nevertheless, it should be understood that the association ofnon-composite numerals and BELTs as illustrated in FIG. 25 is merely anexample of how non-composite numerals may be associated with BELTs in aparticular embodiment, and that many other association embodiments maybe used without departing from the claimed subject matter. Thisparticular association embodiment, however, makes use of an associationof BELTs and natural numerals. FIG. 27 is a table illustrating aparticular embodiment of an association between natural numerals BELTs.Here, the resulting BELTs may be used as tags corresponding tonon-composite node label values of nodes in a node labeled tree and/orfactors thereof. As illustrated in particular embodiments above, thesetags are attached to corresponding nodes in the resulting BELT by edgeshaving a label value of binary zero (in which a tag is connected by anedge having a label value of binary zero). It should be recognized thatBELTs corresponding to numerals zero and one are used to represent tagscorresponding to node label values zero and one as illustrated in FIG.25. As illustrated in FIG. 27, the tags associated with non-compositenode label values and/or factors three, five, seven, eleven and thirteencorrespond with the BELTs associated with numerals two, three, four,five and six, respectively. This matches the association ofnon-composite numerals greater than two and BELT portions shown in FIG.25

Such an association of BELTs and numerals as illustrated may begenerated by an enumeration of BELTs and associating natural numerals tosuch enumerated BELTs. Thus, for this particular embodiment, althoughthe claimed subject matter is not limited in scope in this respect, amethod of enumerating a set of trees begins with enumeration of an emptybinary edge labeled tree and a one node binary edge labeled tree. Here,the empty tree is associated with the zero and has a symbolicrepresentation as illustrated in FIG. 27 (circle). Likewise, the onenode tree, which holds no data, is associated with the one and has agraphical representation of a single node. For higher positive naturalnumerals, however, this embodiment of a method of enumerating a set oftrees comprises positioning a tree at location k, k being a positivenumeral greater than three, in which k comprises the product of u and v,u and v comprising positive numerals greater than one, such that thetree is formed by a union of the trees at positions u and v. Likewise,for those locations that are not a product of other natural positivenumerals greater than one, that is, for locations that comprisenon-composite numerals, denoted here by j, for example, j being apositive natural numeral greater than one, a tree is positioned atlocation j such that the tree is formed by finding the first tree in theprior enumeration such that the binary edge labeled tree obtainable fromthis first tree by attaching a node to the particular tree as a new rootnode and labeling the edge between the new root node and the prior rootnode with a binary zero label is not in the enumeration at some positionlower than j; however, if the binary edge labeled tree obtainable fromthat first tree, as just described, is present in the enumeration with abinary zero label for the new edge, but not with a binary “1” label,then the tree at position j is that tree with a binary “1” label for thenew edge. This may be illustrated, for example in FIG. 27, as describedin more detail below.

For a particular embodiment, although the claimed subject matter is notlimited in scope in this respect, a method of enumerating a set ofordered trees may begin with enumeration of an empty binary edge labeledtree and a one node binary edge labeled tree. Thus, the empty tree isassociated with the zero and has a symbolic representation asillustrated in FIG. 27 (circle). Likewise, the one node tree, whichholds no data, is associated with the one and has a graphicalrepresentation of a single node. For higher positive natural numerals,ordered trees may be generated by a process described, for example, in“The Lexicographic Generation of Ordered Trees,” by S. Zaks, The Journalof Theoretical Computer Science, Vol. 10(1), pp. 63-82, 1980, orEnumerating Ordered Trees Lexicographically,” by M. C. Er, ComputationJournal, Vol. 28, Issue 5, pp. 538-542, 1985.

As illustrated, for this particular embodiment, and as previouslydescribed, the empty tree has zero nodes and is associated with thezero. Likewise, the one node tree root comprises a single node and isassociated with the one. Thus, to obtain the tree at position two, aroot node is attached and connected to the prior root node by an edge.Likewise, here, by convention, the edge is labeled with a binary zero.If, however, the tree formed by the immediately proceeding approach werepresent in the prior enumeration of trees, then a similar processembodiment is followed, but, instead, the new edge is labeled with abinary one rather than a binary zero. Thus, for example, in order toobtain the binary edge labeled tree for position three, a new root nodeis connected to the root node by an edge and that edge is labeled with abinary one.

Continuing with this example, to obtain the binary edge labeled tree forposition four, observe that numeral four is the product of numeral twotimes numeral two. Thus, a union is formed at the root of two trees,where, here, each of those trees is associated with the positive naturalnumeral two. Likewise, to obtain the binary edge labeled tree forposition five, begin with the binary edge labeled tree for position twoand follow the previously articulated approach of adding a root and anedge and labeling it with a binary zero.

In this context, adding a root node and an edge and labeling it binaryzero is referred to as a “zero-push” operation and adding a root nodeand an edge and labeling it binary one is referred to as a “one-push”operation. Based at least in part on the prior description, for thisparticular embodiment, it may now be demonstrated that if k is anypositive natural numeral and a tree is positioned at location k, then anon-composite numeral is associated with the zero-push of that tree anda non-composite numeral is associated with the one-push for that tree.Furthermore, the non-composite index of the zero-push of the treecomprises 2k−1, whereas the non-composite index of the one-push of thetree comprises 2k, where the index corresponds to the argument of thewell-known Kleene enumeration on positive natural numerals ofnon-composite numerals, as illustrated, for example, in part in FIG. 28.Thus, referring again to FIG. 27, the one-push of the root tree is thetree at position three. This follows from FIG. 27 since P(2*1)=P(2)=3.Likewise, the tree at position five is the zero-push of the tree atposition 2. Again, this follows from FIG. 28 since P(2*2−1)=P(3)=5.

The embodiments illustrate in FIGS. 5 through 23 involve connecting tags(BELT portions representing node label values and/or factors thereof) tounlabeled nodes by edges having a label value of binary zero and assignan edge label value of binary one to the remaining edges in theresulting BELT. In alternative embodiments, however, such edgesconnecting tags may have a label value of binary one with the remainingedges having a label value of binary zero, although the claimed subjectmatter is not limited in these respects.

Also, the transformations illustrated above with reference to FIGS. 5through 23 are particularly directed to transforming an unlabeled treeand/or a node labeled tree to a BELT. However, it should be recognizedthat, as a BLT may essentially be represented as either a BELT or aBNLT, such techniques illustrated herein would equally apply to therepresentation of hierarchical data of an unlabeled tree and/or nodelabeled tree in a BNLT.

Techniques for performing table look ups are well-known andwell-understood. Thus, this will not be discussed in detail here.However, it shall be appreciated that any and all of the previouslydescribed and/or later described processing, operations, conversions,transformations, manipulations, etc. of strings, trees, numerals, data,etc. may be performed on one or more computing platforms or similarcomputing devices, such as those that may include a memory to storetables although, the claimed subject matter is not necessarily limitedin scope to this particular approach. Thus, for example, a hierarchy ofdata may be formed by combining two or more hierarchies of data, such asby applying a previously described embodiment. Likewise, multiplehierarchies of data may be formed by splitting or dividing a particularhierarchy of data, again, such as by applying a previously describedembodiment. Likewise, additional operations and/or manipulations of datahierarchies may be performed, such as ordering hierarchies of data andmore. It is intended that the claimed subject matter cover all suchembodiments.

It will, of course, be understood that, although particular embodimentshave just been described, the claimed subject matter is not limited inscope to a particular embodiment or implementation. For example, oneembodiment may be in hardware, such as implemented to operate on adevice or combination of devices, for example, whereas anotherembodiment may be in software. Likewise, an embodiment may beimplemented in firmware, or as any combination of hardware, software,and/or firmware, for example. Likewise, although the claimed subjectmatter is not limited in scope in this respect, one embodiment maycomprise one or more articles, such as a storage medium or storagemedia. This storage media, such as, one or more CD-ROMs and/or disks,for example, may have stored thereon instructions, that when executed bya system, such as a computer system, computing platform, or othersystem, for example, may result in an embodiment of a method inaccordance with the claimed subject matter being executed, such as oneof the embodiments previously described, for example. As one potentialexample, a computing platform may include one or more processing unitsor processors, one or more input/output devices, such as a display, akeyboard and/or a mouse, and/or one or more memories, such as staticrandom access memory, dynamic random access memory, flash memory, and/ora hard drive, although, again, the claimed subject matter is not limitedin scope to this example.

In the preceding description, various aspects of the claimed subjectmatter have been described. For purposes of explanation, specificnumbers, systems and/or configurations were set forth to provide athorough understanding of the claimed subject matter. However, it shouldbe apparent to one skilled in the art having the benefit of thisdisclosure that the claimed subject matter may be practiced without thespecific details. In other instances, well-known features were omittedand/or simplified so as not to obscure the claimed subject matter. Whilecertain features have been illustrated and/or described herein, manymodifications, substitutions, changes and/or equivalents will now occurto those skilled in the art. It is, therefore, to be understood that theappended claims are intended to cover all such modifications and/orchanges as fall within the true spirit of the claimed subject matter.

What is claimed is:
 1. A method comprising: executing instructions by aprocessor; the method comprising: transforming an unlabeled tree to abinary labeled tree (BLT), said unlabeled tree and BLT being elementaryequivalents; wherein said transforming said unlabeled tree to said BLTfurther comprises: transforming said unlabeled tree to a node labeledtree, said unlabeled tree and said node labeled tree being elementaryequivalents; and transforming said node labeled tree to said BLT;wherein nodes in said node labeled tree are associated with node labelvalues, and wherein said transforming said node labeled tree to said BLTfurther comprises representing node label values of selected ones ofsaid nodes in said node labeled tree as one or more nodes coupled tonodes in said BLT corresponding with said selected nodes; wherein saidnode label values are associated with numerals, and wherein saidrepresenting node label values of selected ones of said nodes in saidnode labeled tree further comprising: associating said node label valuesof said selected nodes in said node labeled tree with corresponding BLTsand/or BLT portions according to an association of trees and numerals;and representing said node label values of said selected nodes in saidBLT with said corresponding BLTs and/or BLT portions.
 2. The method ofclaim 1, wherein said BLT comprises a binary edge labeled tree.
 3. Anapparatus comprising: means for defining an unlabeled tree; and meansfor transforming said unlabeled tree to a binary labeled tree (BLT),said unlabeled tree and BLT being elementary equivalents; wherein saidmeans for transforming said unlabeled tree to said BLT furthercomprises: means for transforming said unlabeled tree to a node labeledtree, said unlabeled tree and said node labeled tree being elementaryequivalents; and means for transforming said node labeled tree to saidBLT; wherein nodes in said node labeled tree are associated with nodelabel values, and wherein said means for transforming said node labeledtree to said BLT further comprises means for representing node labelvalues of selected ones of said nodes in said node labeled tree as oneor more nodes coupled to nodes in said BLT corresponding with saidselected nodes; and wherein said node label values are associated withnumerals, and wherein said means for representing node label values ofselected ones of said nodes in said node labeled tree furthercomprising: means for associating said node label values of saidselected nodes in said node labeled tree with corresponding BLTs and/orBLT portions according to an association of trees and numerals; andmeans for representing said node label values of said selected nodes insaid BLT with said corresponding BLTs and/or BLT portions.
 4. Theapparatus of claim 3, wherein said BLT comprises a binary edge labeledtree.
 5. An apparatus comprising: means for defining a node labeledtree; and means for transforming said node labeled tree to a binarylabeled tree (BLT), said node labeled tree and BLT being elementaryequivalents; wherein nodes in said node labeled tree are associated withnode label values, and further comprising means for representing nodelabel values of selected ones of said nodes in said node labeled tree asone or more nodes coupled to nodes in said BLT corresponding with saidselected nodes; wherein said node label values are associated withnumerals, and wherein said means for representing node label values ofselected ones of said nodes in said node labeled tree further comprises:means for associating said node label values of said selected nodes insaid node labeled tree with corresponding BLTs and/or BLT portionsaccording to an association of trees and numerals; and means forrepresenting said node label values of said selected nodes in said BLTby extending said corresponding BLTs and/or BLT portions from nodes insaid BLT associated with said selected nodes in said node labeled tree.6. The apparatus of claim 5, wherein said BLT comprises a binary edgelabeled tree.
 7. An article comprising: a non-transitory storage mediumcomprising machine-readable instructions stored thereon to transform anunlabeled tree to a binary labeled tree (BLT), said unlabeled tree andBLT being elementary equivalents; wherein the non-transitory storagemedium further comprises machine-readable instructions stored thereonto: transform said unlabeled tree to a node labeled tree, said unlabeledtree and said node labeled tree being elementary equivalents; andtransform said node labeled tree to said BLT; wherein nodes in said nodelabeled tree are associated with node label values, and wherein thenon-transitory storage medium further comprises machine-readableinstructions stored thereon to represent node label values of selectedones of said nodes in said node labeled tree as one or more nodescoupled to nodes in said BLT corresponding with said selected nodes;wherein said node label values are associated with numerals, and whereinthe storage medium further comprises machine-readable instructionsstored thereon to: associate said node label values of said selectednodes in said node labeled tree with corresponding BLTs and/or BLTportions according to an association of trees and numerals; andrepresent said node label values of said selected nodes in said BLT withsaid corresponding BLTs and/or BLT portions.
 8. An article comprising: anon-transitory storage medium comprising machine-readable stored thereonto: transform a node labeled tree to a binary labeled tree (BLT), saidnode labeled tree and BLT being elementary equivalents; wherein nodes insaid node labeled tree are associated with node label values, andwherein the storage medium further comprises machine-readableinstructions stored thereon to represent node label values of selectedones of said nodes in said node labeled tree as one or more nodescoupled to nodes in said BLT corresponding with said selected nodes;wherein said node label values are associated with numerals, and whereinthe storage medium further comprises machine-readable instructionsstored thereon to: associate said node label values of said selectednodes in said node labeled tree with corresponding BLTs and/or BLTportions according to an association of trees and numerals; andrepresent said node label values of said selected nodes in said BLT withsaid corresponding BLTs and/or BLT portions.
 9. An apparatus comprisinga computing platform, the computing platform comprises a memorycomprising instructions stored therein which are executable, thecomputing platform being adapted to: transform an unlabeled tree to abinary labeled tree (BLT), said unlabeled tree and BLT being elementaryequivalents; wherein the computing platform is further adapted to:transform said unlabeled tree to a node labeled tree, said unlabeledtree and said node labeled tree being elementary equivalents; andtransform said node labeled tree to said BLT; wherein nodes in said nodelabeled tree are associated with node label values, and wherein thecomputing platform is further adapted to represent node label values ofselected ones of said nodes in said node labeled tree as one or morenodes coupled to nodes in said BLT corresponding with said selectednodes; wherein said node label values are associated with numerals, andwherein the computing platform is further adapted to: associate saidnode label values of said selected nodes in said node labeled tree withcorresponding BLTs and/or BLT portions according to an association oftrees and numerals; and represent said node label values of saidselected nodes in said BLT with said corresponding BLTs and/or BLTportions.
 10. The apparatus of claim 9, wherein said BLT furthercomprises a binary edge labeled tree.
 11. An apparatus comprising acomputing platform the computing platform comprises a memory comprisinginstructions stored therein which are executable, the computing platformbeing adapted to: transform a node labeled tree to a binary labeled tree(BLT), said node labeled tree and BLT being elementary equivalents;wherein nodes in said node labeled tree are associated with node labelvalues, and wherein the computing platform is further adapted torepresent node label values of selected ones of said nodes in said nodelabeled tree as one or more nodes coupled to nodes in said BLTcorresponding with said selected nodes, wherein said node label valuesare associated with numerals, and wherein the computing platform isfurther adapted to: associate said node label values of said selectednodes in said node labeled tree with corresponding BLTs and/or BLTportions according to an association of trees and numerals; andrepresent said node label values of said selected nodes in said BLT withsaid corresponding BLTs and/or BLT portions.
 12. The apparatus of claim11, wherein said BLT further comprises a binary edge labeled tree.
 13. Amethod comprising: executing instructions by a processor; the methodcomprising: transforming a node labeled tree to binary labeled tree,said node labeled tree and BLT being elementary equivalent; whereinnodes in said node labeled tree are associated with node label values,and further comprising representing node label values of selected onesof said nodes in said node labeled tree as one or more nodes coupled tonodes in said BLT corresponding with said selected nodes; wherein saidnode label values are associated with numerals, and wherein saidrepresenting node label values of selected ones of said nodes in saidnode labeled tree further comprises: associating said node label valuesof said selected nodes in said node labeled tree with corresponding BLTsand/or BLT portions according to an association of trees and numerals;and representing said node label values of said selected nodes in saidBLT by extending said corresponding BLTs and/or BLT portions from nodesin said BLT associated with said selected nodes in said node labeledtree.
 14. The article of claim 7, wherein said BLT comprises a binaryedge labeled tree.
 15. The article of claim 8, wherein said BLTcomprises a binary edge labeled tree.
 16. The method of claim 13,wherein said BLT comprises a binary edge labeled tree.